Security systems use a number of different types of sensors to determine if an intruder has entered a protected space. They include Doppler microwave sensors, passive infrared (PIR) sensors, acoustic sensors, magnetic contact sensors, and dual technology sensors that combine microwave and PIR sensors together. The Doppler microwave sensors transmit a microwave frequency signal and detect a change in the return signal due to the presences of an intruder. Since these sensors monitor the protected space at a high rate they detect all motion. A problem occurs when the motion is not from a person, which causes a false alarm. The PIR sensors detect motion from a person because they sense the “heat” (IR) emanating from the person, but in a high ambient temperature environment the PIR sensor will not sense a change in “temperature” and therefore will not detect the motion of an intruder. The acoustic sensors determine when glass has been broken, but the intruder may enter the protected space without breaking glass or the acoustic sensor may not catch a single quick act of breaking glass. The magnetic contact sensors are used to determine if a door or window has been opened by an intruder, but these sensors do not give the user flexibility to leave a window open while enabling the security system and also do not detect the intruder if he does not enter the protected space through a door or window. Finally, sensors with dual technology (i.e. PIR and Doppler microwave sensors) reduce false alarms and enhance detection of the intruder, but when there is no verification from one of the sensors, an intruder may not be detected. It is desirable to have a security system that reliably detects an intruder under all conditions without false alarms or missed catch.
In addition, it is desirable to increase the protection of a premises when the user is present and to increase the user's flexibility to open doors or windows without generating a false alarm. Typical security systems employ motion sensors that are enabled when the premises is vacant (daytime mode) and disabled when the occupants are present (nighttime mode). During the nighttime mode, the security system relies on magnetic contact and/or glass break sensors to determine when there has been an intrusion. In this mode the occupants must disable the security system when opening a door to, for instance, let a pet outside. In addition, if an intruder does not enter through a door or window with a magnetic contact and/or glass break sensor, he will not be detected. Warning a user of an impending intrusion and deterring the intruder from entering the premises is also desirable to increase the protection of the premises when the occupants are present.
In addition, it is desirable to provide the location of the intruder and/or the occupants of the premises. The location of the occupants would be useful for firefighters when rescuing occupants, or for everyday use in locating an absent person.
It is object of the present invention to provide a security system that reliably detects an intruder without false alarms.
It is a further object of the present invention to increase the protection of a premises from an intruder while increasing the user's flexibility to open doors or windows without generating a false alarm.
It is a further object of the present invention to warn the occupants of an impending intrusion and to deter the intruder from entering the premises.
Finally, it is a further object of the present invention to provide a security system that displays the location of an intruder and/or the location of the occupants of a premises.